Biobased asphalt rejuvenating emulsion

ABSTRACT

A polymer-modified emulsion used for rejuvenating or repairing deteriorated asphalt pavement includes an asphalt phase containing an asphalt and a biobased rejuvenating agent, and an aqueous phase including water and an emulsifying agent, and one or more polymers included in the asphalt phase, the aqueous phase or both.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/192,930 filed Jul. 15, 2015 and U.S. Provisional PatentApplication No. 62/262,701 filed Dec. 3, 2015, the disclosure of eachare herein incorporated by reference in their entirety.

TECHNICAL FIELD

This invention relates to modified asphalt emulsions for road surfacetreatments.

BACKGROUND

Asphalt concrete, also known as asphalt pavement, is a compositematerial that includes mineral aggregate and an asphalt (bitumen) binderwhich hardens to form a robust surface. Asphalt pavement deterioratesover time from oxidation of asphalt binder, heavy loads and varyingclimatic conditions. One method for restoring or repairing deterioratedasphalt pavement is to remove and replace the existing pavement witheither newly prepared or recycled pavement. Removal and replacement,however, is expensive and wasteful.

SUMMARY OF THE INVENTION

Rather than removing and replacing deteriorated pavement, it ispreferable to restore the pavement using a surface treatment. In oneaspect, this disclosure is directed at a polymer-modified asphaltrejuvenating emulsion comprising:

an asphalt phase comprising an asphalt and at least one biobasedrejuvenating agent;

an aqueous phase comprising water and an emulsifying agent; and

one or more polymers included in the asphalt phase, the aqueous phase orboth.

In another aspect, this disclosure provides a method for rejuvenatingdeteriorated asphalt, which method comprises:

-   -   a) providing a polymer-modified asphalt emulsion comprising an        asphalt phase which includes an asphalt and at least one        biobased rejuvenating agent, an aqueous phase which includes        water and an emulsifying agent, and one or more polymers        included in the asphalt phase, the aqueous phase or both; and    -   (b) applying the asphalt emulsion to a deteriorated asphalt        pavement surface.

Another aspect of this disclosure is directed to a rejuvenated asphaltpavement comprising a polymer-modified asphalt rejuvenating emulsionatop a deteriorated asphalt pavement, the rejuvenating emulsioncontaining an asphalt phase comprising an asphalt and at least onebiobased rejuvenating agent, an aqueous phase comprising water and anemulsifying agent, and one or more polymers included in the asphaltphase, the aqueous phase or both.

The disclosed polymer-modified asphalt rejuvenating emulsions containingbiobased rejuvenating agents are suitable for road maintenance ofdeteriorated asphalt pavement, thereby extending the life and service ofthe pavement.

DETAILED DESCRIPTION

The term “about” refers to a range of numbers that is consideredequivalent to the recited value (e.g., having the same function orresult). In many instances, the term “about” may include numbers thatare rounded to the nearest significant figure.

The term “biobased” refers to compositions from natural or biologicalresources, including derivatives or modifications thereof.

The term “polymer” includes, independently, homopolymers, copolymers,terpolymers, block copolymers, segmented copolymers, graft copolymers,and any mixture or combination thereof.

The term “deteriorated” refers to cracked, aged, oxidized or distressedasphalt pavement, for example distressed includes asphalt pavementidentified by Miller, John S., and William Y. Bellinger. Distressidentification manual for the long-term pavement performance program.No. FHWA-HRT-13-092. 2014.

The term “emulsifying agents” refer to surfactants (includingbiodegradable surfactants) and to stabilizing agents. Emulsifying agentsmaintain the asphalt material in a stable suspension and control theemulsion breaking time, where the breaking time is the time required forthe emulsified asphalt materials to separate from the aqueous phasepermitting water evaporation and formation of a cured or set coating.

The term “meth” in parentheses, such as “(meth)acrylate,” refers eitherto the acrylate or to the methacrylate, or mixtures of both. Similarly,the term (meth)acrylamide refers either to the acrylamide or to themethacrylamide, or mixtures of both.

Numerical ranges expressed using endpoints include all numbers subsumedwithin that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4 and5).

All percentages are weight percentages.

Disclosed is an asphalt rejuvenating emulsion that includes at least onebiobased rejuvenating agent in the asphalt phase of the emulsion.Additionally, one or more polymers may be added to either an asphaltphase, the aqueous phase, or both phases of the asphalt rejuvenatingemulsion to enable an asphalt pavement surface treatment or aninterlayer treatment in conjunction with other treatments. Thesetreatments may be used, for example, as a rejuvenator, scrub seal, fogseal, sand seal, chip seal, tack coat, bond coat, crack filler or as amaterial for prevention of reflective cracking. The treatments enableuse of a wide variety of asphalts for restoring and rejuvenatingdeteriorated road pavement.

In certain embodiments, the rejuvenating agent in the asphalt phase mayrevitalize the asphalt and permit continued use and service on roadwayswhile the polymer may offer durability to the pavement as well aspotentially filing surface cracks or preventing the propagation of suchcracks.

The disclosed emulsion may be a mixture of components that interact withone another. As a consequence, the concentration of one component may beincreased within certain limits if the concentration of another iscorrespondingly decreased, without significantly altering the propertiesof the resulting composition. The disclosed emulsion may be applied toan existing base or substrate of a pavement. The disclosed emulsionincludes an asphalt phase which includes asphalt and at least onerejuvenating agent, an aqueous phase, which includes water andemulsifying agents, and one or more polymers included in either or bothof the phases. The emulsion provides a cationic, anionic, non-ionic, orneutral character to the final emulsion depending upon the desiredemulsion's electrochemical properties or the intended emulsion use, forexample, the surface type on which the emulsion is to be applied. Thedisclosed emulsion desirably includes substantial asphalt content. Forexample, the asphalt concentration may be about 30% to 70% of the totalweight of the emulsion.

Various asphalt grades may be used in the disclosed asphalt emulsioncomposition depending on the expected pavement temperatures. The asphaltcomposition grades used in the emulsion may be defined by thePerformance Grade (PG) values of the Strategic Highway Research Program(SHRP) or the American Association of State Highway and TransportationOfficials (AASHTO) M320 standards. The asphalt composition grades mayfor example include about PG-94 (about 5-10 pen) to about PG-52 (about160-220 pen), about PG-88 (about 10-20 pen) to about PG-64 (about 50-70pen), or about PG-64 (about 50-70 pen) to about PG-52 (about 160-220pen).

The asphalts used may be, for example, oxidized or air-blown asphalts,non-oxidized asphalts and blends thereof. In other aspects, the asphaltincludes, but is not limited to, asphalt produced from atmosphericdistillation, vacuum distillation, solvent extraction, air, orcombinations of these methods. Still other asphalts may includenaturally occurring asphalts such as gilsonite, asphaltites, and thelike.

Asphalt blowing, also referred to as oxidation or air rectification, maybe used to produce oxidized or air blown asphalt of desired consistencyfrom a softer asphalt than the final asphalt product yielded by theblowing process. The desired result of the blowing process is anincrease in softening point and a reduction in penetration values overthat of the starting, base asphalt. Typically, the blowing processincludes heating the base asphalt, generally to a temperature of 232.2°C. (450° F.) to 260° C. (500° F.), and blowing air into the hot asphaltfor a period of time required to yield the desired properties. Theblowing process is a temperature-time dependent process with an inverserelationship of temperature and time. Thus, at higher temperatures theblowing time is generally less than the time required to achieve thesame properties at lower temperature. The exchange surface or contactsurface between the hot asphalt and the air forced into it generallyalso is a factor in determining the blowing process length and therequired air quantity.

Maltenes are the non-asphaltene fraction of asphalt, referred to asdeasphalted or deasphaltened oil. The maltene fraction of asphaltincludes polar resins, and aromatic and saturated solvents. Adeteriorated asphalt may exhibit a low level of maltenes. Petroleumbased rejuvenating agents, such as for example, Reclamite RA-1 fromTricor Refining, LLC have been used to replenish maltenes in asphaltpavement. However, such petroleum based rejuvenating agents are notrenewable resources. In accordance with this disclosure, the deficiencyof the maltene fraction in deteriorating asphalt may be made up byreplacing it with a biobased rejuvenating agent. In certain embodiments,the biobased rejuvenating agent is capable of penetrating the surface ofthe aged and deteriorated asphalt to replenish at least a portion of themaltene fraction with, for example, a biobased oil or ester thereof andrestore some of the original properties to the asphalt. The amount ofthe biobased rejuvenating agent in the emulsion can be adjusteddepending on the pavement surface condition where the emulsion will beapplied. If the surface is deteriorated asphalt concrete, the amount ofbiobased rejuvenating agent can be increased to ensure adequate dosingof the deteriorated asphalt concrete to restore the maltene fraction ofthe deteriorated asphalt.

Biobased rejuvenating agents may include oils or esters from natural orbiological resources, including derivatives or modifications thereof.Without being bound by theory, it is believed that the biobasedrejuvenating agent may function as softening agents for the bitumen inasphalt pavement. The current US Army Corps of Engineers (USACE) unifiedfacilities guide specification (UFGS) for bituminous rejuvenation (UFGS02787) suggests that the asphalt cement or binder recovered from theupper 9.5 mm of a pavement shall have a decrease in viscosity of atleast 40% with respect to untreated material. Non-limiting examples ofbiobased rejuvenating agents include one or more of a vegetable oil orester thereof, a seed oil or ester thereof, a soybean oil or esterthereof, a corn oil or ester thereof, a palm oil or ester thereof, acanola oil or ester thereof, a safflower oil or ester thereof, asunflower oil or ester thereof, a citrus oil or ester thereof, pine oilor ester thereof, a rosin oil or ester thereof, or a biobased fatty acidester. Exemplary commercially available rejuvenating agents includethose available from Cargill Incorporated under the Agri-Pure Gold®brand (such as Agri-Pure Gold 53, 55, 63S, 67, 135, 142S, 200, 500,750S, and 2000) and the Anova® brand asphalt rejuvenators, thoseavailable from Arizona Chemical, LLC under the SYLVAROAD™ brand, andthose available from the Archer Daniels Midland Company. In certainembodiments, seed oils may be preferred rejuvenating agents. In otherembodiments, the tree based oils such as pine oil or rosin oil may bepreferred.

The asphalt rejuvenating emulsion preferably employs biobasedrejuvenating agents (sometimes also called recycling agents) in amountssuitable to permit the penetration of the biobased rejuvenating agentinto the surface of the aged and deteriorated asphalt. The amount ofbiobased rejuvenating agent may for example be from about 0.5%, about1%, and preferably about 2% to about 15%, 10% or preferably 8% by totalweight of the emulsion. The ratio of the biobased rejuvenating agent tothe polymer may for example be from 1:10 to 5:1, from 1:3 to 3:1, from1:2 to 2:1, or about 1:1. The amount of biobased rejuvenating agent mayalso be such that an asphalt's viscosity is restored for example toabout 1,000 to about 3,000 centipoise at 60° C. Those of ordinary skillin the art are capable of selecting a specific biobased rejuvenatingagent and the specific amount of the rejuvenating agent in the emulsionto achieve the desired restoration of a deteriorated asphalt pavement.

The asphalt rejuvenating emulsions of this disclosure include one ormore polymers in the asphalt phase, the aqueous phase or both. Exemplarypolymers include those that assist in providing desired properties forthe asphalt emulsion residue, for example by, providing astress-absorbing layer that strongly adheres to the underlying pavement,by providing a non-tacky surface, or by providing a polymer with anon-swelling nature. The polymers may for example be about 1%, 2% or 3%to about 15%, 10% or 6% by total weight of the emulsion. The selectionof a specific polymer or polymers for a rejuvenating application maydepend upon many variables such as, for example, the type of pavement,pavement conditions, weather cycles, seasonal weather conditions,traffic volumes, etc. Those of ordinary skill in the art with knowledgeof this disclosure are capable of selecting an appropriate polymer orpolymers to assist in the desired rejuvenation of a particular pavement.Additionally, those of ordinary skill in the art will recognize that thecombination of polymers in one or both phases of the emulsion mayprovide particular advantages in rejuvenating pavement.

In some embodiments, the asphalt phase incorporates one of more polymersas a modifier to enhance specific physical characteristics of theresulting residue. Exemplary polymers include those that assist inproviding desired properties for the asphalt emulsion residue. Thepolymers may for example be about 4% to 8% by weight of the asphaltphase or about 1% to about 15% by total weight of the emulsion.

Various embodiments of the asphalt rejuvenating emulsion of thisdisclosure may include any elastomer or plastomer. Non-limiting examplesof such polymers include styrene-butadiene rubber,styrene-butadiene-styrene rubber, polychloroprene, styrene butadieneplastomers, polyurethanes, thermoplastic olefins (for example, oxidizedpolyethylene wax or ethylene terpolymer), thermoplastic polyamides, oracrylate terpolymers (for example, glycidyl methacrylate).

In other embodiments, the one or more polymers may be utilized in theemulsion as a dispersion and added to the aqueous phase. Exemplarylattices of styrene butadiene rubber, styrene-butadiene-styrene andpolychloroprene as well as others may be incorporated into the aqueousphase of the asphalt rejuvenating emulsion.

In some embodiments, acrylic polymers may be well suited for use in theasphalt rejuvenating emulsions. Acrylic polymers are often supplied as adispersion and therefore may be included in the aqueous phase of theemulsion. The acrylic polymer or copolymers are preferably derived fromacrylate monomers. The acrylate monomers may for example be based on(meth)acrylic acid, esters of (meth)acrylic acid, (meth)acrylamide,(meth)acrylonitrile and derivatives of these acrylate monomers.Exemplary esters of (meth)acrylic acids include, but are not limited to,alkyl and hydroxyalkyl esters, e.g., methyl (meth)acrylates, ethyl(meth)acrylates, butyl (meth)acrylates, hydroxyethyl (meth)acrylate,isobornyl (meth)acrylate, and longer chain alkyl (meth)acrylates such asethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate,and stearyl (meth)acrylate. Derivatives of (meth)acrylamide include, butare not limited to, alkyl substituted (meth)acrylamides, e.g.,N,N-dimethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, t-butyl(meth)acrylamide, N-octyl (meth)acrylamide, and longer chain alkyl(meth)acrylamides such as N-lauryl (meth)acrylamide and N-stearyl(meth)acrylamide. The acrylic polymers also include polymers commonlyknown as acrylics, acrylate polymers, polyacrylates or acrylicelastomers. Acrylate polymers belong to a group of polymers which couldbe referred to generally as plastics while acrylic elastomer is ageneral term for a type of synthetic rubber whose main component is anacrylic acid alkyl ester (for example, an ethyl or butyl ester).

Exemplary copolymers include polymers derived from polyolefins such asvinyl acetate, vinyl chloride, vinylidene chloride, styrene, substitutedstyrene, butadiene, unsaturated polyesters, ethylene and the like. Insome embodiments, the acrylic copolymer is derived from acrylatemonomers and mixtures thereof and polymerized with styrene or ethylene.In still other embodiments, the acrylic copolymer is derived from butylacrylate and copolymerized with styrene or ethylene. In yet otherembodiments, the copolymer may be an acrylonitrile butadiene.

Exemplary acrylic polymers or copolymers include those available fromthe BASF Corporation under the ACRONAL™ brand (such as ACRONAL NX 4627and ACRONAL NX 4627 X) and those available from Bayer MaterialScience AGunder the BAYHYDROL™ brand. Other exemplary acrylic polymers orcopolymers are available from Michelman under the LICOMER™ brand, fromWacker under the VINNAPAS™ brand, from Synothomer under the REVACRYL™brand, from Arkema under the ENCOR™ brand, and from Westlake under theEBAC™ brand.

With certain applications, it may be desirable to incorporate one ormore polymers in each of the asphalt phase and the aqueous phase. Theincorporation of multiple polymers in this manner may permit theselective combination to achieve desired physical characteristics.Alternatively, it may be desirable in certain embodiments to incorporatedifferent polymers into a single phase of the asphalt rejuvenatingemulsion.

There are typically four categories of emulsifying agents, namelycationic, anionic, amphoteric and nonionic. Depending on the type ofemulsifying agent used, an acid or a base may be needed to activate theemulsifying agent. When cationic emulsifying agents are used, acid maybe added to adjust the emulsion pH to between 1.0 and 7.0. Suitableacids include inorganic acids, for example hydrochloric acid andphosphoric acid. The acid promotes a positive charge on the emulsifyingagent. A subcategory of cationic emulsifying agents, known as quaternaryammonium salts, do not require acid activation because the charge isbuilt into the emulsifying agent.

When anionic emulsifying agents are used, base may be added to adjustthe emulsion pH to between 7.0 and 12.0. Suitable bases includeinorganic bases, for example sodium hydroxide and potassium hydroxide.The base promotes a negative charge on the emulsifying agent.

When amphoteric emulsifying agents are used both the cationic andanionic chemical functionality are built into the same molecule.Therefore, either functionality may be activated; the cationic portionmay be activated by acid or the anionic portion may be activated bybase.

When nonionic emulsifying agents are used, it may not be necessary toactivate the emulsifying agent with either acid or base.

The amount of emulsifying agent should preferably be sufficient tomaintain a stable emulsion. The concentration can vary based on the typeof emulsifying agents used and other components of the emulsion but isgenerally from greater than 0 to about 5% by weight of the emulsion, forexample from about 0.01% to about 3.0% by weight of the emulsion.

Exemplary cationic emulsifying agents include polyamines, fatty amines,fatty amido-amines, ethoxylated amines, propoxylated amines, diamines,imidazolines, quaternary ammonium salts, and mixtures thereof.Commercial cationic emulsifying agents include, for example, thoseavailable from Akzo Nobel Surface Chemistry under the REDICOTE™ brand(including REDICOTE 4819, REDICOTE E-64R, REDICOTE E16, REDICOTE E-9,REDICOTE EM-44, REDICOTE C-346, REDICOTE E-7000 and REDICOTE E-70), andfrom MeadWestvaco Corporation under the INDULIN™ brand (includingINDULIN F-80, INDULIN DF-60, INDULIN DF-40, INDULIN DF-42, INDULINDF-30, INDULIN R-20, INDULIN AA 54, INDULIN AA 56, INDULIN AA 57,INDULIN AA-71, INDULIN AA-78, INDULIN AA-83, INDULINAA-86 and INDULINAA-89).

Exemplary anionic emulsifying agents include alkali metal or ammoniumsalts of fatty acids, alkali metal polyalkoxycarboxylates, alkali metalN-acylsarcosinates, alkali metal hydrocarbylsulphonates, for example,sodium alkylsulphonates, sodium arylsulphonates, sodiumalkylarylsulphonates, sodium alkylarenesulphonates, sodiumlignosulphonates, sodium dialkylsulphosuccinates and sodium alkylsulphates, long chain carboxylic and sulphonic acids, their salts andmixtures thereof.

Exemplary amphoteric emulsifying agents include betaines and amphotericimidazolinium derivatives.

Exemplary non-ionic emulsifying agents include ethoxylated compounds andesters, for example ethoxylated fatty alcohols, ethoxylated fatty acids,sorbitan esters, ethoxylated sorbitan esters, ethoxylated alkylphenols,ethoxylated fatty amides, glycerine fatty acid esters, alcohols, alkylphenols, and mixtures thereof.

The emulsion may contain other additives to adjust the emulsionproperties in relation to the planned use, application method, andstorage conditions. These include, for example, mineral salts,thickening agents, stabilizing agents, anti-freeze agents, adhesionpromoters, biocides, pigments and the like.

Exemplary stabilizing agents may include polysaccharides, e.g.,biodegradable glucopyranose, glycans such as β-D glucans, scleroglycans(CAS No. 39464-87-4), schizophyllan (CAS No. 9050-67-3), laminaran (CASNo. 9008-22-4), cinerean, lentinan (CAS No. 37339-90-5), curdlan (CASNo. 54724-00-4) glucose polymers, preservatives, and the like. Otherstabilizing agents may include cellulose compounds or derivativesthereof, e.g. microcrystalline cellulose (AVICEL™ RC591), ethylcelluloseand gunge (NATRASOL™).

Exemplary thickening agents include scleroglucan, scleroglucan modifiedwith glyoxal or with another reactant, guar gum, gum arabic, ghatti gum,karaya gum, gum tragacanth, locust bean gum, xanthan gum, andwater-soluble polyurethanes resulting in particular from the reaction ofone or more polyisocyanates with one or more polyols chosen frompolyester polyols and polyether polyols.

Other exemplary thickening agents are available from Latexfalt, b.v.Koudekerd a/d Rijn, The Netherlands and as described in WO 2009/113854A1.

The weight percentage of the asphalt phase of the emulsion may forexample represent from about 30% to about 70% of the total emulsionweight. The corresponding aqueous phase of the emulsion may for examplerepresent from about 70% to about 30% of the total emulsion weight. Theemulsifying agents or other additives may represent from about 0.01% toabout 3.0% of the total emulsion weight, and preferably from about 0.5%to about 3.0% of the total emulsion weight.

The disclosed asphalt emulsions may be prepared by mixing, in nospecific order, the emulsifying agent, the optional polymer and waterand adjusting the pH of the resulting emulsifying agent solutiondepending on the emulsifying agent type. The emulsifying agent solutionmay for example be heated from slightly above room temperature to up toabout 70° C. Separately, the asphalt, the biobased rejuvenating agentand optional polymer blend may for example be heated to 130° C. to 160°C., depending upon the viscosity of the asphalt and biobasedrejuvenating agent blend used. For example, a low viscosity asphalt suchas a PG 52 might be heated to only 130° C. and a high viscosity asphaltsuch as a PG 64 might be heated as high as 160° C. The emulsion may beformed at ambient pressure or under pressure with subsequent cooling tobelow 100° C. (212° F.) before exposure to the atmosphere. The asphaltphase and the emulsifying agent solution may be mixed or injected into ahigh-speed, high shear mechanical mixer, such as a colloid mill or otherequipment capable of emulsifying the constituents to produce the asphaltemulsion. The temperature of the finished emulsion desirably ismaintained, for example, below about 100° C. (212° F.), for example fromabout 71° C. (160° F.) to 99° C. (210° F.). The use of such temperaturespermits operation of the mixer at ambient pressure and avoids boilingthe aqueous phase and consequent interference with the emulsificationprocess. The ratio of the asphalt and emulsifying agent solution isadjusted to produce an asphalt emulsion containing a desired amount ofasphalt material, which may for example be from 30 to 70%.

In the above-described method, the polymer may be added into theemulsifying agent solution, the asphalt phase or both. Alternatively,the asphalt emulsion can be produced with direct injection, where theasphalt, biobased rejuvenating agent and emulsifying agent (without thepolymer) are injected into the colloid mill through individual supplylines and the polymer is directly injected into the asphalt supply linejust ahead of the colloid mill. The polymer-modified asphalt with abiobased rejuvenating agent can also be produced by post-addition, wherethe desired amount of the polymer is added into a pre-manufacturedemulsion containing asphalt and biobased rejuvenating agent but withoutthe polymer.

The emulsion should remain stable during storage and typically may bestored for about 14 days, depending on the constituents. Some settlingmay occur, but a light (simple) agitation of the emulsion usuallyre-disperses asphalt into the emulsion.

A final emulsion may also be prepared from a concentrate emulsion bydiluting the concentrate emulsion with sufficient additional water toprovide the desired asphalt or additive content in the final emulsion.

The specific weight percentages of the asphalt phase and the aqueousphase in the final emulsion may be chosen depending on factors such asthe preexisting pavement composition or the base course materials andconditions, or the number of planned applications, the desired curetime, and user agency regulations or specifications. Similarly, theemulsifying agents, stabilizing agents, and other additives may beadjusted for specific application conditions, asphaltic materials, andsubstrates.

The final emulsion is preferably formulated such that, afterapplication, the emulsion rejuvenates the deteriorated asphalt byrestoring the aromatic content and forms a stress absorbing layer whichstrongly adheres to the underlying pavement.

The final emulsion may be prepared in advance of its application or at awork site immediately before its application. If desired, theconcentrate may be mixed with water at a rate sufficient to produce thedesired final emulsion on a continuous basis during application usingmetering and mixing equipment known to those skilled in the art.

The final asphalt emulsion may be applied by hand spreading,conventional spreading, spraying, or other techniques. A recommendedapplication rate may be, for example, about 0.045 to about 2.7liters/sq. meter (about 0.01 to about 0.60 gal/sq. yd.) or about 0.14 toabout 2.0 liters/sq. meter (about 0.03 to about 0.45 gal/sq. yd.). Theemulsion can be applied in multiple passes over the substrate layers atlower rates to achieve a comparable product, where the total applicationrate is equal to the sum of the multiple passes and is from about 0.045liters/sq. meter to about 2.7 liters/sq. meter (about 0.01 to about 0.60gal/sq. yd.). For example, an emulsion may be applied in three passesover the substrate layer at application rates of 0.04 liters/sq. meter(about 0.01 gal/sq. yd.) each, or a total application rate of about 0.12liters/sq. meter (0.03 gal/sq. yd.). The emulsion application rate mayalso vary depending on the specified application conditions, emulsioncomposition, the surface to which it is applied, and the nature of thepermanent materials or base (viz., the pavement structure), and othersimilar factors.

The emulsion temperature during application may, for example, be fromabout 4° C. (40° F.) to about 99° C. (210° F.), from about 49° C. (120°F.) to about 77° C. (170° F.), or from about 38° C. (100° F.) to about71° C. (160° F.). Alternatively, the emulsion may be at ambienttemperature (e.g. about 20° C. to 25° C. (68° F. to 77° F.), but if soapplied may require a longer curing time. The emulsion typically isplaced on top of a deteriorated surface and is allowed to cure beforetraffic passes over the coated surface or additional pavement layer(s)are applied to the coated surface.

The emulsions may generally be formulated to achieve a desired residueupon breaking of the emulsion and drying or removal of the aqueousportion. The procedures for recovering the residue are set forth in theExamples section of this disclosure. In certain embodiments, residuerecovery may generally range from about 30% to about 70% by weight ofthe emulsion.

Complex modulus may be another characteristic suitable for demonstratingthe effectiveness of the emulsion. In certain applications, the complexmodulus can be an indication of the stiffness or strength of the residueof the emulsion. Complex modulus is determined using a dynamic shearrheometer to, often over an extended period of time, to determine thecharacteristics of the residue under controlled stress and strain. Theprocedure for determining the complex modulus is set forth in theExamples section of this disclosure. The specific grade of asphalt andthe type and amount of polymer employed in the emulsion may impact thereported complex modulus.

The disclosed composition is further illustrated in the followingnon-limiting examples. Various modifications and alterations of thedisclosed compositions will be apparent to those skilled in the artwithout departing from the scope of this disclosure.

EXAMPLES

Asphalt Emulsion Residue Procedure: Two methods were used to recoverasphalt residues from exemplary emulsions. Emulsion residue verificationwas determined in accordance with ASTM International D7944-15 StandardPractice for Recovery of Emulsified Asphalt Residue Using a Vacuum Oven.This practice is suitable for recovery of the residue of emulsifiedasphalts composed principally of a semisolid or liquid asphaltic base,water and an emulsifying agent. Asphalt base may be pre-modified withpolymeric modifiers or latex polymer modifiers may be incorporated intothe emulsified asphalt through co-milling or post emulsified asphaltproduction blending. The method consists of a three hour thin filmrecovery of residue from an emulsion in a 60° C. vacuum oven.

In certain Examples, emulsion residues for subsequent physical propertyevaluation, complex modulus testing, were obtained in accordance withASTM International D7497-09 Standard Practice for Recovering Residuefrom Emulsified Asphalt Using Low Temperature Evaporative Technique. Theprocedure is used to obtain a residue from an emulsified asphalt thatmay be used for further testing in devices such as a dynamic shearrheometer. The lower evaporative temperatures of this procedure provideconditions that are very close to that of application techniques forthese materials. This practice is used in place of recovery techniquesat higher temperatures that are not representative of typical emulsionapplication techniques. Under D7497-09, emulsions in thin films aredried for one day under forced airflow at 60° C. to provide emulsionbinder residues.

Complex Modulus Test procedure: A dynamic shear rheometer (DSR) isutilized to determine the complex modulus. The test reports the complexmodulus (G*) as an indicator of the stiffness or resistance of asphaltbinder to deformation under load. Complex modulus and phase angle defineresistance to shear deformation of an asphalt binder in the linearviscoelastic region. The Complex Modulus Test is conducted on residuerecovered from asphalt emulsions in accordance with ASTM InternationalD7175-15 Standard Test Method for Determining the Rheological Propertiesof Asphalt Binder Using a Dynamic Shear Rheometer. ASTM D7175-15determines the dynamic modulus and phase angle of asphalt binders whentested in dynamic (oscillatory) shear using parallel plate geometry. Itis applicable to asphalt binders having dynamic modulus values in therange from 100 Pa to 10 MPa. This range in modulus is typically obtainedbetween 4 and 88° C. at 10 radians/second. Results are obtained at 50°C. using 25 mm diameter parallel plates at a 1 mm gap testing at 10radian/second.

The materials used to create the Examples are set forth in Table 1.

TABLE 1 Materials Asphalt PG 64-22 from Ergon Asphalt & Emulsions, Inc.Jackson, MS. Soy Derived Oil RBD Soy Oil from Archer Daniels MidlandCompany, Chicago, IL. Pine Derived Oil SYLVAROAD ™ RP 1000 from ArizonaChemical, Jacksonville, FL. Corn Derived Oil RBD Corn Oil from ArcherDaniels Midland Company, Chicago, IL. Peanut Derived Oil Lou-Ana RefinedPeanut Oil from Ventura Foods, Opelousas, LA. RA-1 Rejuvenating Oil RA-1Petroleum-based Rejuvenating Oil from Tricor Refining, LLC, Bakersfield,CA. Emulsifying Agent Redicote E-7000 from Akzo Nobel Surface ChemistryLLC, Chicago, IL. HCL Hydrochloric acid Acrylic Latex Acronal 4627X fromBASF Corporation, Florham Park, NJ. SBR Latex Styrene-butadiene rubberNeoprene polychloroprene

Examples 1-4 are polymer-modified asphalt emulsions produced utilizingvarious biobased rejuvenating agents. Each of the Examples were preparedby mixing the materials shown in Table 1 at the weight percentagesindicated in Table 2. For all of the Examples, the emulsifying agent andacrylic latex were mixed with water and its pH adjusted to below 3 withHCl. The resulting emulsifying agent solution was heated from slightlyabove room temperature to about 40.° C. Separately, the asphalt andbiobased rejuvenating agent blend were heated to about 130° to 160° C.The emulsifying agent solution and heated asphalt and rejuvenating agentblend were injected into a colloid mill to produce the asphalt emulsion.The temperature of the finished emulsion was maintained below about 100°C. (212° F.). Table 3 indicates the results of testing on each of theresulting emulsions for Examples 1-4. Each Example was tested forpercent retention of solids on a 20 mesh sieve, viscosity and particlesize. Additionally, the asphalt emulsion residue was recovered byAsphalt Emulsion Residue Procedure using ASTM International D7944-15.The recovered residue is reported in Table 3.

TABLE 2 Formulations Example 1 Example 2 Example 3 Example 4 RawMaterial Wt % Wt % Wt % Wt % Asphalt 52.90 52.90 52.90 52.90 Soy DerivedOil 6.67 Sylva Road 6.67 Corn Derived Oil 6.67 Peanut Derived Oil 6.67Emulsifier 2.00 2.00 2.00 2.00 HCL 0.20 0.20 0.20 0.20 Acrylic Copolymer3.00 3.00 3.00 3.00 water 35.23 35.23 35.23 35.23 100 100 100 100

TABLE 3 Results Emulsion Test Example 1 Example 2 Example 3 Example 4Sieve % 0.072 0.093 0.08 0.046 25° C. Viscosity, sec 140.26 90.91 74.65134.48 Particle Size, μm 26.77 12.82 20.01 15.23 Residue, % 59.3 62.1659.31 61.42

Example 5

Emulsions for Example 5 were prepared as described in Examples 1-4, withpetroleum based RA-1 rejuvenating agent included for comparisonpurposes. The examples include 2% or 3% acrylic copolymer solids in theemulsion residues. The biobased rejuvenating agents were substituted ata level to provide an equivalent viscosity to a use level ofapproximately 10% RA-1 rejuvenating agent. Emulsions were dried inaccordance with ASTM International D7497-09 to provide emulsion binderresidues. Table 4 lists the measured complex modulus of the emulsionbinder residues, as tested under the Complex Modulus Test. The chosendrying conditions illustrate the initial strength development of theasphalt emulsion binder after resumption of a traffic condition.

TABLE 4 TABLE 4 Measured Complex Modulus of Emulsion Residue at 50° C.Polymer Level in Acrylic Copolymer Solids in the Emulsion EmulsionResidue 2% 3% RA-1 Rejuvenating Oil 5.63 6.32 Peanut Derived Oil 3.935.02 Soy Derived Oil 4.37 4.22 Corn Derived Oil 4.97 5.23 Pine Oil 3.613.55

Example 6

The strength development of polymer modified emulsions containing 2% or3% polymer solids were tested over a period of several days afterapplication and measured using Dynamic Shear Rheometry. The emulsionswere prepared as in Examples 1-4. The emulsion residues were preparedusing ASTM International D7497-09 and were aged by storing in a darkforced airflow oven at 60° C. for 10 days and the residue complexmodulus values were measured at 1 day, 3 days, 7 days and 10 days aging.The results are reported in Table 5.

TABLE 5 Measure Complex Modulus of Emulsion Residue at 50° C. OvenCuring Time at 60° C. 0 day 1 day 3 day 7 day 10 day RA-1 RejuvenatingOil 2% Polymer 5.63 8.73 13.00 20.20 25.80 3% Polymer 6.32 10.10 14.2023.00 26.90 Peanut Derived Oil 2% Polymer 3.93 5.63 8.65 11.10 13.30 3%Polymer 5.02 5.97 9.57 10.40 12.10 Soy Derived Oil 2% Polymer 4.37 6.179.40 12.40 15.26 3% Polymer 4.22 6.94 11.60 12.20 15.95 Corn Derived Oil2% Polymer 4.97 7.87 12.12 13.18 14.90 3% Polymer 5.23 8.16 11.30 14.7415.20 Pine Derived Oil 2% Polymer 3.61 4.80 9.65 9.08 9.70 3% Polymer3.55 5.25 8.52 8.25 10.30

Table 5 shows measured complex modulus as a function of aging. Theseresults demonstrate both the early strength development and agedstrength of the acrylic-modified asphalt emulsions containing biobasedrejuvenating agent as compared to the acrylic-modified asphalt emulsionscontaining the petroleum based RA-1 rejuvenating agent.

Example 7

Emulsions were prepared as described in Example 5, with biobasedrejuvenating agents and polymer dispersions as set forth in Table 6. Thepolymers were incorporated to establish 2% and 3% acrylic copolymersolids in the emulsion residues. For comparative purposes results fromemulsions containing an RA-1 rejuvenating agent with Neoprene, SBR Latexand an Acrylic Latex were formulated and tested. Biobased rejuvenatingagents were substituted at a level to provide an equivalent viscosity toa use level of approximately 10% RA-1 rejuvenating agent. Emulsions weredried for one day under forced airflow at 60° C. to provide emulsionbinder residues. Table 8 lists the measured complex modulus of theemulsion binder residues at 50° C. as a function of the type of oil andamount of acrylic polymer solids in the emulsion residue. The complexmodulus illustrates the strength of the emulsion residue undercontrolled stress and strain representing a traffic condition. Thechosen drying conditions illustrate the initial strength development ofthe asphalt emulsion binder after resumption of a traffic condition.

Table 6:

TABLE 6 Measured Complex Modulus of Emulsion Residue at 50° C. PolymerLevel in the Emulsion Residue 2% 3% RA-1 Rejuvenating Oil Neoprene 0.800.85 SBR Latex 1.10 1.20 Acrylic Latex 5.63 6.32 Peanut Derived OilNeoprene 2.36 3.04 SBR Latex 4.39 5.40 Acrylic Latex 3.93 5.02 SoyDerived Oil Neoprene 3.68 4.84 SBR Latex 5.51 6.42 Acrylic Latex 4.374.22 Corn Derived Oil Neoprene 4.54 5.76 SBR Latex 6.81 8.36 AcrylicLatex 4.97 5.23 Pine Derived Oil Neoprene 3.68 3.72 SBR Latex 4.24 4.68Acrylic Latex 3.61 3.55

Example 8

The strength development of polymer modified emulsions containing 2% or3% polymer solids were tested over a period of several days afterapplication and measured using Dynamic Shear Rheometry. The emulsionswere prepared as in Example 5. After 1 day forced airflow drying at 60°C., the emulsion residues were aged by storing in a dark forced airflowoven at 60° C. for 10 days and the residue complex modulus values weremeasured at 1 day, 3 days, 7 days and 10 days aging. The results arereported in Table 7.

TABLE 7 TABLE 7 Measure Complex Modulus of Emulsion Residue at 50° C.Oven Curing Time at 60° C. 0 day 1 day 3 day 7 day 10 day RA-1Rejuvenating Oil 2% Polymer Neoprene 0.80 1.10 1.10 1.20 1.40 SBR Latex1.10 1.50 1.80 2.00 2.10 Acrylic Latex 5.63 8.73 13.00 20.20 25.80 3%Polymer Neoprene 0.85 1.20 1.60 1.70 2.20 SBR Latex 1.20 2.00 2.30 2.302.30 Acrylic Latex 6.32 10.10 14.20 23.00 26.90 Peanut Derived Oil 2%Polymer Neoprene 2.36 3.60 8.22 6.61 7.88 SBR Latex 4.39 7.85 11.7015.00 17.50 Acrylic Latex 3.93 5.63 8.65 11.10 13.30 3% Polymer Neoprene3.04 4.21 10.80 14.50 8.21 SBR Latex 5.40 7.94 12.80 15.00 18.30 AcrylicLatex 5.02 5.97 9.57 10.40 12.10 Soy Derived Oil 2% Polymer Neoprene3.68 5.79 15.60 11.20 14.17 SBR Latex 5.51 9.97 11.90 20.68 19.15Acrylic Latex 4.37 6.17 9.40 12.40 15.26 3% Polymer Neoprene 4.84 7.4310.20 14.10 15.32 SBR Latex 6.42 10.50 14.70 24.40 21.19 Acrylic Latex4.22 6.94 11.60 12.20 15.95 Corn Derived Oil 2% Polymer Neoprene 4.547.74 13.10 20.10 21.60 SBR Latex 6.81 11.60 18.30 20.43 25.10 AcrylicLatex 4.97 7.87 12.12 13.18 14.90 3% Polymer Neoprene 5.76 9.82 13.4017.33 20.70 SBR Latex 8.36 13.20 19.30 24.74 27.00 Acrylic Latex 5.238.16 11.30 14.74 15.20 Pine Derived Oil 2% Polymer Neoprene 3.68 5.779.78 11.70 26.65 SBR Latex 4.24 6.60 9.93 11.60 14.00 Acrylic Latex 3.614.80 9.65 9.08 9.70 3% Polymer Neoprene 3.72 5.80 9.80 15.88 13.78 SBRLatex 4.68 7.37 10.64 16.11 46.20 Acrylic Latex 3.55 5.25 8.52 8.2510.30

Table 7 shows measured complex modulus as a function of aging. Theseresults clearly demonstrate both the early strength development and agedstrength of the neoprene, SBR Latex and Acrylic Latex modified asphaltemulsions containing biobased rejuvenating agent as compared to theneoprene, SBR and acrylic copolymer modified asphalt emulsionscontaining petroleum based RA-1 rejuvenating agent.

Although specific embodiments have been illustrated and described hereinfor purposes of description of the preferred embodiments, it will beappreciated by those of ordinary skill in the art that a wide variety ofalternate or equivalent implementations calculated to achieve the samepurposes may be substituted for the specific embodiments shown anddescribed without departing from the scope of the present invention.This application is intended to cover any adaptations or variations ofthe preferred embodiments discussed herein. Therefore, it is manifestlyintended that this invention be limited only by the claims and theequivalents thereof.

1. A polymer-modified asphalt rejuvenating emulsion comprising: a stableliquid dispersion containing an asphalt phase comprising an asphalt andat least one biobased rejuvenating agent; an aqueous phase comprisingwater and an emulsifying agent; and one or more polymers included in theasphalt phase, the aqueous phase or both.
 2. The emulsion of claim 1,wherein the asphalt phase comprises from about 30% to about 70% of thetotal weight of the emulsion.
 3. The emulsion of claim 1, wherein the atleast one biobased rejuvenating agent comprises a biobased oil or esterthereof.
 4. The emulsion of claim 1, wherein the at least one biobasedrejuvenating agent comprises one or more of a vegetable oil or esterthereof, a seed oil or ester thereof, a soybean oil or ester thereof, acorn oil or ester thereof, a palm oil or ester thereof, a canola oil orester thereof, a safflower oil or ester thereof, a sunflower oil orester thereof, a citrus oil or ester thereof, pine oil or ester thereof,a rosin oil or ester thereof, a biobased fatty acid ester, or acombination thereof.
 5. The emulsion of claim 1, wherein the at leastone biobased rejuvenating agent comprises about 2% to about 15% of thetotal weight of the emulsion.
 6. The emulsion of claim 1, wherein theone or more polymers is an acrylic polymer.
 7. The emulsion of claim 6,wherein the acrylic polymer comprises a butyl (meth)acrylate polymer, anethyl (meth)acrylate polymer or a derivative thereof, a styrene-butylacrylate copolymer, or an ethylene butyl acrylate copolymer.
 8. Theemulsion of claim 1, wherein the one or more polymers comprises anelastomer or plastomer.
 9. The emulsion of claim 1, wherein the one ormore polymers comprises styrene butadiene rubber,styrene-butadiene-styrene or polychloroprene.
 10. The emulsion of claim1, wherein the one or more polymers comprises about 1% to about 15% ofthe total weight of the emulsion.
 11. The emulsion of claim 1, whereinthe emulsifying agent comprises from about 0.01% to about 3.0% of thetotal weight of the emulsion.
 12. A method for rejuvenating deterioratedasphalt, which method comprises: a) providing a polymer-modified asphaltemulsion comprising a stable liquid dispersion containing an asphaltphase which includes an asphalt and at least one biobased rejuvenatingagent, an aqueous phase which includes water and an emulsifying agent,and one or more polymers included in the asphalt phase, the aqueousphase or both; and b) applying the asphalt emulsion to a deterioratedasphalt pavement surface.
 13. The method of claim 12, wherein theasphalt phase comprises from about 30% to about 70% of the total weightof the emulsion.
 14. The method of claim 12, wherein the one or morepolymers comprises a butyl (meth)acrylate polymer, an ethyl(meth)acrylate polymer, a styrene-butyl acrylate copolymer, or anethylene butyl acrylic copolymer.
 15. The method of claim 12, whereinthe at least one biobased rejuvenating agent comprises a biobased oil orester thereof.
 16. The method of claim 12, wherein the emulsifying agentcomprises from about 0.01% to about 3.0% of the total weight of theemulsion.
 17. The method of claim 12, comprising applying the emulsionto the deteriorated asphalt pavement surface in an amount of about 0.045to about 2.7 liters per square meter.
 18. The method of claim 12,comprising applying the emulsion to the deteriorated asphalt pavementsurface at an emulsion temperature of about 4° C. to about 99° C.
 19. Arejuvenated asphalt pavement comprising a polymer-modified asphaltrejuvenating emulsion atop a deteriorated asphalt pavement, therejuvenating emulsion containing an asphalt phase comprising an asphaltand at least one biobased rejuvenating agent, an aqueous phasecomprising water and an emulsifying agent, and one or more polymersincluded in the asphalt phase, the aqueous phase or both.
 20. Therejuvenated asphalt pavement of claim 19, wherein the at least onebiobased rejuvenating agent comprises a biobased oil or ester thereof.